Documents disponibles écrits par cet auteur

Peroxide−acetic acid pretreatment to remove bagasse lignin prior to enzymatic hydrolysis / Tan, He in Industrial & engineering chemistry research, Vol. 49 N° 4 (Fevrier 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 4 (Fevrier 2010) . - pp 1473–1479 Titre : Peroxide−acetic acid pretreatment to remove bagasse lignin prior to enzymatic hydrolysis Type de document : texte imprimé Auteurs : Tan, He, Auteur ; Yang, Rallming, Auteur ; Sun, Weidong, Auteur Année de publication : 2010 Article en page(s) : pp 1473–1479 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Peroxide-acetic  acid  Enzymatic  hydrolysis. Résumé : This paper presents results on the features of bagasse pretreatment with peroxide and acetic acid (peroxide−HAc) aiming at selective removal of lignin to enhance enzymatic hydrolysis. Surface response methodology was employed to study the effects of major process parameters on delignification and to establish a model for the prediction of lignin removal in the process. Enzymatic hydrolysis following the pretreatment was conducted to evaluate the enhancement of biohydrolysis by the pretreatment. Results revealed that peroxide−HAc pretreatment of bagasse retained most of the carbohydrate constituents, although the delignification rate was low. Peroxide−HAc concentration, temperature, and time demonstrated significant effects on bagasse lignin removal. The relationship between lignin removal and the process parameters could be well described by a mathematical model derived from the experimental data. After treatment with 69.1% peroxide−HAc at 80 °C for 26.5 h, 97.08% of lignin could be removed while keeping 68.24% hemicelluloses intact. Over 93.58% of carbohydrate in treated bagasse could be hydrolyzed with exoglucanase in a dosage of 138 FPU/g carbohydrates at 35 °C within 48 h. It was thus demonstrated that treated bagasse has a much higher response toward enzymatic hydrolysis than its untreated counterpart. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901529q [article] Peroxide−acetic acid pretreatment to remove bagasse lignin prior to enzymatic hydrolysis [texte imprimé] / Tan, He, Auteur ; Yang, Rallming, Auteur ; Sun, Weidong, Auteur . - 2010 . - pp 1473–1479. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 4 (Fevrier 2010) . - pp 1473–1479 Mots-clés : Peroxide-acetic  acid  Enzymatic  hydrolysis. Résumé : This paper presents results on the features of bagasse pretreatment with peroxide and acetic acid (peroxide−HAc) aiming at selective removal of lignin to enhance enzymatic hydrolysis. Surface response methodology was employed to study the effects of major process parameters on delignification and to establish a model for the prediction of lignin removal in the process. Enzymatic hydrolysis following the pretreatment was conducted to evaluate the enhancement of biohydrolysis by the pretreatment. Results revealed that peroxide−HAc pretreatment of bagasse retained most of the carbohydrate constituents, although the delignification rate was low. Peroxide−HAc concentration, temperature, and time demonstrated significant effects on bagasse lignin removal. The relationship between lignin removal and the process parameters could be well described by a mathematical model derived from the experimental data. After treatment with 69.1% peroxide−HAc at 80 °C for 26.5 h, 97.08% of lignin could be removed while keeping 68.24% hemicelluloses intact. Over 93.58% of carbohydrate in treated bagasse could be hydrolyzed with exoglucanase in a dosage of 138 FPU/g carbohydrates at 35 °C within 48 h. It was thus demonstrated that treated bagasse has a much higher response toward enzymatic hydrolysis than its untreated counterpart. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901529q

Polysulfide distribution during kraft pulping / Sujit Banerjee in Industrial & engineering chemistry research, Vol. 49 N° 8 (Avril 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 8 (Avril 2010) . - pp. 3983–3985 Titre : Polysulfide distribution during kraft pulping Type de document : texte imprimé Auteurs : Sujit Banerjee, Auteur ; Yang, Rallming, Auteur Année de publication : 2010 Article en page(s) : pp. 3983–3985 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Polysulfi  Kraft  Pulping  Kraft  Pul Résumé : Polysulfides increase yield from kraft pulping by selectively oxidizing the reducing end groups of the polysaccharides thereby protecting them from hydrolysis. The principal polysulfide homologue formed in white liquor after addition of elemental sulfur was found to be the S22− species. Analysis of both cooking liquor and wood chips during early cooking suggests that the polysulfide present in the chips degrades more slowly than the fraction dissolved in the bulk liquor. The alkalinity inside the chips is lower than that in the bulk liquor. We propose that the rate of degradation of the polysulfides contained within the chip is correspondingly reduced. As pulping proceeds and the structure of the chips open up, the diffusion barrier across the chip is reduced and the polysulfide concentration in the chip and in the bulk liquor begins to even out. It follows that pre-equilibration of wood chips with polysulfide before pulping may reduce the optimum polysulfide dose. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100176x [article] Polysulfide distribution during kraft pulping [texte imprimé] / Sujit Banerjee, Auteur ; Yang, Rallming, Auteur . - 2010 . - pp. 3983–3985. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 8 (Avril 2010) . - pp. 3983–3985 Mots-clés : Polysulfi  Kraft  Pulping  Kraft  Pul Résumé : Polysulfides increase yield from kraft pulping by selectively oxidizing the reducing end groups of the polysaccharides thereby protecting them from hydrolysis. The principal polysulfide homologue formed in white liquor after addition of elemental sulfur was found to be the S22− species. Analysis of both cooking liquor and wood chips during early cooking suggests that the polysulfide present in the chips degrades more slowly than the fraction dissolved in the bulk liquor. The alkalinity inside the chips is lower than that in the bulk liquor. We propose that the rate of degradation of the polysulfides contained within the chip is correspondingly reduced. As pulping proceeds and the structure of the chips open up, the diffusion barrier across the chip is reduced and the polysulfide concentration in the chip and in the bulk liquor begins to even out. It follows that pre-equilibration of wood chips with polysulfide before pulping may reduce the optimum polysulfide dose. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100176x

Scanning electron microscopy measurements of the surface roughness of paper / Sujit Banerjee in Industrial & engineering chemistry research, Vol. 48 N° 9 (Mai 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 9 (Mai 2009) . - pp. 4322–4325 Titre : Scanning electron microscopy measurements of the surface roughness of paper Type de document : texte imprimé Auteurs : Sujit Banerjee, Auteur ; Yang, Rallming, Auteur ; Charles E. Courchene, Auteur Année de publication : 2009 Article en page(s) : pp. 4322–4325 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Paper  sheet  X-y  uniformity  Roughness  Scanning  electron  microscopy Résumé : A new approach to the measurement of x−y uniformity of the surface of a paper sheet is described. Scanning electron micrographs are taken of both the top and bottom surfaces of a paper sheet and image-analyzed. The images were converted to grayscale, and the standard deviation of the pixel brightness was called the “SEM roughness index” and calculated for each surface. Both commercial newsprint sheets and handsheets made with kraft, TMP, and recycled fibers were examined. Debonders and cationic polymers were added to some sheets. The addition of debonders increases the index on the top side of the sheet but decreases it on the bottom. This is caused by the movement of fines from the top to the bottom side. The addition of cationic polymers increases the SEM roughness index by increasing the degree of microfloc formation. Samples taken across a reel from a commercial paper machine tend to show a mirror image relationship between the top and bottom surfaces. The SEM roughness index is able to detect subtle changes in sheet structure caused by differences in the mode of addition of polymers used for retaining fines in the sheet. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900029v [article] Scanning electron microscopy measurements of the surface roughness of paper [texte imprimé] / Sujit Banerjee, Auteur ; Yang, Rallming, Auteur ; Charles E. Courchene, Auteur . - 2009 . - pp. 4322–4325. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 9 (Mai 2009) . - pp. 4322–4325 Mots-clés : Paper  sheet  X-y  uniformity  Roughness  Scanning  electron  microscopy Résumé : A new approach to the measurement of x−y uniformity of the surface of a paper sheet is described. Scanning electron micrographs are taken of both the top and bottom surfaces of a paper sheet and image-analyzed. The images were converted to grayscale, and the standard deviation of the pixel brightness was called the “SEM roughness index” and calculated for each surface. Both commercial newsprint sheets and handsheets made with kraft, TMP, and recycled fibers were examined. Debonders and cationic polymers were added to some sheets. The addition of debonders increases the index on the top side of the sheet but decreases it on the bottom. This is caused by the movement of fines from the top to the bottom side. The addition of cationic polymers increases the SEM roughness index by increasing the degree of microfloc formation. Samples taken across a reel from a commercial paper machine tend to show a mirror image relationship between the top and bottom surfaces. The SEM roughness index is able to detect subtle changes in sheet structure caused by differences in the mode of addition of polymers used for retaining fines in the sheet. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900029v